Susceptibility weighted imaging (SWI) has become an important new tool for diagnosing disease in the brain. It is used to study the vasculature of the brain, to detect iron in the brain and to visualize micro-hemorrhages. The method relies on changes in susceptibility between tissues that lead to the introduction of phase differences between tissues and to signal loss. It has been shown to be a powerful means to better diagnose trauma, stroke and tumors and detect changes in brain function. We wish to continue the development of SWI to: a) make it more clinically viable by reducing phase processing artifacts; b) evaluate susceptibility itself by creating a susceptibility map of human tissue; c) study its role as a new MR angiographic method by simultaneously collecting MRA and SWI data; and d) speed up its acquisition time to less than 5 minutes for whole brain coverage, independent of any parallel imaging gain factor. The solution of these problems offers not only an advance over the current use of SWI but also the introduction of important new research directions in magnetic resonance imaging methods. To accomplish these goals, we will perform simulations to mimic expected human conditions, perform phantom experiments to establish the accuracy of the techniques, and perform human experiments to validate the methodology in vivo. The proposed research will take place over four years with the early parts devoted to technical development and the latter parts to potential clinical applications on volunteers. These studies will include: imaging the susceptibility of tissues in the brain, measuring oxygen saturation in major vessels and collecting whole brain vascular information for the arteries and veins. These methods will also be evaluated with and without contrast agents when it comes to testing the angiographic elements of the proposal. The success of this research program will offer a means to better detect neurological and vascular disease. [unreadable] [unreadable] PUBLIC HEALTH REVELANCE: Susceptibility Weighted Imaging (SWI) is a new high resolution magnetic resonance imaging method that makes it possible to detect microhemorrhages and iron content in the brain. This exquisite sensitivity to iron in the form of blood products (such as hemosiderin) and ferritin makes SWI the method of choice for imaging neurological diseases such as trauma, stroke, multiple sclerosis, and tumors. Recently, SWI has also become available to the clinical world for every day use and therefore its continued technical development is of paramount importance for the proper diagnosis of these diseases in patients. [unreadable] [unreadable] [unreadable]